It is not only desirable to protect the environment from debris, particulates, contaminants, biologics, bacteria, chemicals and other airborne material which are produced in industrial plants but to provide similar protection in systems which have a fluid flow that are used in hospital anesthesia systems, plumbing and combustion equipment such as boilers, incinerators and chimneys.
Filtration devices in a plumbing system are used for the soil vent stack. However, the prior art devices are difficult to install in existing system and once installed are difficult to maintain.
Hospitals utilize a central location for gases used in delivery to patients in their rooms or in the operating rooms. A problem recognized in hospitals is that contaminants such as mold or pathogens are capable of growth in the delivery systems and require frequent inspection and cleaning. Such operation is not efficient and is costly. New Jersey at the present time is the only state which requires maintenance of any gas delivery system. It would be desirable to provide a system which can be easily installed that filters any undesirable matter found in the oxygen or anesthesia systems.
Any industrial operation involving the generation of dust, smoke and other forms of particulate matter or biologics entrained in a gas or the generation of noxious gases mixed with harmless gases that are discharged into the atmosphere should provide for removal of the objectionable materials to the greatest possible extent before the gas is discharged. This invention relates to a filter system and/or arrangement that allow more efficient and reliable operation, permits more effective maintenance of the equipment, and also frequently provides installation of the equipment at a significantly lower cost, than have been possible with systems and arrangements previously proposed or used.
One problem with previously proposed multiple unit equipment is that the gas flow distribution frequently is not uniform either among the units or within the individual units themselves. As a consequence, one unit may be loaded beyond its efficiency while a companion unit receives only a part of its rated load. This condition does not allow optimum utilization of the gas-cleaning equipment or efficient operation of the cleaning systems.
Moreover, the arrangement of conduits in known multiple unit equipment is often such that poor gas distribution within the separate units causes uneven loading of the cleaning elements of the units and an accompanying deterioration in cleaning performance. In other words, the cross-sectional flow distribution within a given unit is not uniform, as it should be for optimum efficiency. Although a uniform cross-sectional distribution of the gas within a filter is essential to its efficient operation, it is difficult to achieve because of the relatively low gas velocity (on the order of five feet per second) at which filters are operated.
Another difficulty is operating gas-cleaning equipment on line with an industrial process has been that of performing routine maintenance, as well as desirable or necessary repairs, on the gas-cleaning equipment without the necessity of shutting down the industrial process being served by the equipment or discharging uncleaned gases into the atmosphere. For example, the smoke from a boiler may be discharged through a single gas-cleaning device, such as an electrostatic precipitator, for removing particulate matter in the smoke before it is discharged to the stack. If repair work or routine maintenance of the precipitator is required, the boiler has to be shut down. Usually, the precipitator is allowed to remain out of service until such time as the boiler is shut down, and dirty gas is discharged in the meantime.
In some instances, large boilers, furnaces and other combustion apparatuses are served by two or more precipitators in parallel with each other. In such multiple unit systems, smoke from the combustion apparatus typically is conducted through separate conduits or tunnels, each of which is equipped with a precipitator, and then the cleaned gases are discharged to a single stack. Here, if any of the filters require service, operation of the combustion apparatus generally will not be interrupted for such service and again only partial gas cleaning is affected.